inverted pillar; pillar placed upside down
Refers to a wooden pillar intentionally placed with its base pointing upward, traditionally believed to cause ominous phenomena or bad luck. Often encountered in folklore or discussions of traditional building superstitions.
See also: 逆柱
In old houses, it was believed that an inverted pillar would invite ominous phenomena.
Compound of 逆さ (sakasa, 'upside down') + 柱 (hashira, 'pillar'). The exact historical origin of the superstition is uncertain, but it is associated with traditional Japanese beliefs about disturbing the natural order of things.